long-range battery electric vehicle with megawatt wireless

Long-Range Battery Electric Vehicle with Megawatt Wireless Charging

Principal Investigator:

Brian LindgrenKenworth Truck Company

Project ID: elt262

DOE Vehicle Technologies Program

2021 Annual Merit Review

This presentation does not contain any proprietary, confidential, or otherwise restricted information

Overview

Slide 2 of 6

Timeline• Start Date: 1 Oct 2019

• End Date: 12 Dec 2022

• 50% Complete

Budget• Total Project Funding:$8M

• DOE share: $5M

• Partner Cost Share: $3M

BarriersBroad acceptance of battery-electric

power for heavy trucks is hampered by:

• RangeTypical today is 100-150 miles/day

• Re-Charge TimeTypical today is 2-10 hours

This project will research, develop and

demonstrate a Class 8 tractor and

charging system capable of two-shift

operation exceeding 400 miles per day.

The tractor will have range of up to 200

miles and can be recharged in 30

minutes.

Project PartnersA strong and diverse team has been

assembled:

• Kenworth Truck Company –Heavy Truck OEM

• UPS – Global Transportation &

Logistics Fleet

• Utah State University – Academic

Institution with Extensive Wireless

Charging Expertise

• WAVE – Technology Startup Producing

& Deploying Wireless Chargers For

Heavy Vehicles

• Seattle City Light – Local

Government-Owned Utility

• Portland General Electric – Local

Public Utility

• Romeo Power– Battery System

Manufacturer

Long-Range Battery Electric Vehicle with Megawatt Wireless Charging elt_262

Relevance

Slide 3 of n

ImpactHeavy-Duty BEVs are struggling to gain

acceptance by trucking fleets.

• Increasing the range of heavy trucks will

allow fleets to more easily integrate BEVs

into daily routes

• Reducing the charge time will allow fleets

to operate BEVs in two-shift operations

• Minimizing battery size while maximizing

daily range will allow a smaller increase

in initial purchase price and a smaller

reduction in payload capability compared

with today’s diesel powertrains

• Wireless power transfer will allow safe

and efficient extreme fast charging with

minimal driver interaction (no large,

heavy cable to wrestle)

Long-Range Battery Electric Vehicle with Megawatt Wireless Charging elt_262

Objectives• Reduced energy use throughout the BEV

system to improve kW-h/mile

• Baseline test vehicles were measured

at an average of 2.65 kW-h/mile

• System efficiencies in traction

motor/inverter, power steering, air

compressor and thermal management

were explored and will be validated

• Megawatt-rate wireless power transfer

• Design and demonstrate safe and

efficient wireless charging at

megawatt rate

• Develop batteries and charge profile

to allow adding 170+ miles of freeway

range in 30 minutes

Milestones

Slide 4 of n Long-Range Battery Electric Vehicle with Megawatt Wireless Charging elt_262

Target Description Achieved Responsible

Sep 2020 Design parameters for the single-stage AC-AC converter Oct 2020 USU

Dec 2020 Preliminary infrastructure plans for charging sites Dec 2020 USU, WAVE, UPS, SCL, PGE

Dec 2020 Go/No-Go Proof-of-Concept charger operation to validate the coil design, control system function, and thermal management

Mar 2021 USU

Mar 2021 Chassis layout: location of components, weight distribution, and high-voltage cable routings

Mar 2021 KW

Jun 2021 Charging site equipment design is completed At risk USU, WAVE, UPS, SCL, PGE

Sep 2021 Key charger components characterized and validated On target USU, WAVE

Dec 2021 Grid electrical power supply in place at charging sites On target SCL, PGE

Dec 2021 Go/No-Go Demonstrate full-scale megawatt wireless charger system in off-vehicle operation

At risk USU, WAVE

Mar 2022 Vehicle is assembled and fully operable On target KW

Jun 2022 Demonstration of the system operation with one megawatt wireless charging on site

On target (All)

Sep 2022 Confirm operations exceed 400 miles per day On target (All)

KW: Kenworth

PGE: Portland General Electric

SCL: Seattle City Light

USU: Utah State Univ

Approach


Develop a Class 8 BEV tractor optimized for

regional-haul use and wireless extreme fast

charging• Usable energy of >500 kW-h allows range up

to 200 miles on a single charge

• Fast-charge capability at up to 1.5C rate

allows up to 400 miles per shift and 2-shift

operation

Develop a wireless charging system capable

of safely & efficiently charging at up to

megawatt rate• Megawatt wireless charging supports 1.5C

rate, allows re-charge on driver’s lunch break

• Engineered magnetic field containment

ensures system meets ICNRP safety standards

• DC-DC efficiency expected to be 92-95%

ICNRP = International Commission on Non-Ionizing Radiation Protection

Previous Accomplishments


Energy Storage Requirements:• Obtained data from Seattle to Portland in range-extended electric tractor-trailer• Included power requirements for the traction motor system plus all accessory drives such

as cooling pumps and fans, power steering, air compressor, HVAC, etc.• Conservative value for energy consumption one-way Seattle to Portland = 462 kW-h• Selected battery system capacity of 660 kW-h

• One-way energy use is <70% of total capacity: allows operation between 20% SOC and90% SOC

• Megawatt charging yields 1.5 C-rate, which is upper end for NMC cells

Magnetics & Electronics Design and

Simulation:• Significant simulation and investigation• Design meets vehicle parameters and charging

requirement• ANSYS simulation results yield path forward for a scaled

prototype pad and shield• Development and testing plans complete• Initial weight and space calculations complete

Magnetic Field Plot Showing Leakage Meets ICNRP Regulations

Accomplishments- Wireless Charger Design

Slide 7 of nLong-Range Battery Electric Vehicle with Megawatt Wireless Charging

elt_262

Key system parameters:• 660 kWh battery @ 1.5 C charging rate• 390 to 475 kWh of energy in 23 to 29 minutes @ 1 MW• 480V 3-ϕ AC input (Grid voltage)• 649 V –755 V DC output (Battery voltage)• 8 inverter modules x 125 kW per module• >90% targeted efficiency• Leakage fields <15 μT (ANSI 14117 standard)• Air gap of 300 mm• Receiver weight < 3125 lbs

Magnetics design:• Key design features

• Power transfer achieved at large air gap (300 mm)• Meets public safety field exposure limits (ANSI 14117)• Integrated electronics in the pad enclosure• Allocated pad space: 5' x 5'• Estimated weight < 3125 lbs• Operating frequency: 85 kHz

• Key innovations:• Developed new optimization method that considers circuit

topology and magnetics design to find optimal designs for maximum performance

• Design avoids complex interleaving which significantly simplifies cooling design

• Designs evaluated:• Active field cancellation vs passive field cancellation• Various aluminum shield designs to minimize impact of truck

chassis

• Matching battery charge profile required 8 modules vs 4.• Established all component parameters in design phase.

• Single stage AC-AC• High Efficiency• No bulky DC link capacitors

Unfolder + T-type converter

Accomplishments- Wireless Charger Testing


elt_262

• Successfully tested one module (125kW) through charge plates.• Achieved 93% DC-DC efficiency in initial test

Parameter Value

Vout 573 volts

Iout 218 amps

Output Power 125 kW

Losses 9.66 kW

DC-DC Efficiency 93%

M

H-Bridge

/ T-Type

VOutVin

IOut

+

-

Iin

Diode BridgeSecondary

Compensation

Primary

Compensation Wireless

Charging

Pads

Accomplishments- Battery Charge Profile


elt_262

• Successfully demonstrated capability to achieve 462 kW in 30 minutes or less• Determined cooling requirements for charge cooling

Charge Profile:• CP-CV (Transition at 72.5%SOC or 45oC or 0.9C) / 0.9C CC-CV• CP-CV Maximum Current Limit of 1.5C• Peak CV Charge Setpoint 4.1V/cell • 0.9C Peak CV Charge Setpoint at 4.15V/cell

Conditions• Tested one 11-kW module (total system will comprise 66 modules) –

results for total pack are extrapolated• 25°C Initial Temperatures for Cells and Coolant• 25°C Ambient• 2.5 LPM Coolant Flow Rate

Initial SOC (%) Total Charge Time

10 29.78 min.

15 34.52 min.

20 47.01 min.

SOC = State Of ChargeCC = Constant CurrentCV = Constant VoltageCP = Constant Power

Aging test data

Accomplishments- BEV Design


elt_262

Key vehicle attributes:• Kenworth mode: T680 Daycab• Wheelbase: 220”• Traction motor power: 350 kW continuous• Two voltage buses: 650V and 12V. All components

>1 kW are 650V• Estimated tare weights:

Front 13,000 lbsRear 14,000 lbsTotal 27,000 lbs

• Tractor is expected to be drivable in August 2021

Current status:• All components on order; many received• Chassis is being fitted with components• Pacing item is motor/inverter/transmission – expected mid-June

Side Pack2 Side HVBatteries

Traction Motor/Inverter/T

ransmission

High-Voltage Power Distribution

Tower Packs

4 Upper HV Batteries

Wireless Charge Plate

Cooling Module

PowerElectronics

BatteryCooling/Chilling

PowerSteering

AirCompressor

FWD

Chassis component locations

Charge plate mounting

Airflow during charging

Thermal systems attributes:• One WEG radiator; 2 refrigerant condensers; 1 large 650V fan• Batteries cooled by chilled Water/Ethylene Glycol (WEG), each of 6

packs in parallel• Cab HVAC shares refrigerant with battery system; heaters separate• Charger cooled by WEG radiator; simulation shows adequate

cooling when charging at 1 MW rate

Prior AMR Comments/Questions

Slide 11 of n elt_262Long-Range Battery Electric Vehicle with Megawatt Wireless Charging

Was energy consumption from SuperTruckII used in this project?

• No, because we needed energy consumption for a specific route (Seattle to Portland and return). A range-extended electric truck was driven on the route, and electrical energy consumption measured. SuperTruckII data were used as a comparison to ensure that results were reasonable.

It was not clear why wireless charging is preferred at this level of power transfer and vehicle

specialization.

• Cable-connected charging at megawatt rate was expected to require a very large cable size (for 1500+ amps), and was expected to need to be a cooled cable. A cooled connector would need to be developed. High-Voltage, High-Current connections may require an electrician to connect, especially at union facilities. Wireless charging avoids these issues.

The cost of the battery and the incremental wireless infrastructure looks cost prohibitive

• Cost remains a concern. The battery system chosen utilizes high-production-volume NMC cells, a choice intended to optimize battery cost, size and weight. Wireless chargers at lower rates have shown commercial advantages, but this remains to be uncovered during this project at megawatt rate.

Collaboration and Coordination


A strong and diverse team of partners has been established:

Kenworth Truck Co. division of PACCAR – Prime RecipientHeavy Truck OEM. Project leadership and vehicle devlopment

UPSGlobal Transportation and Logistics Fleet. Providing location for charging equipment; will operate test vehicle in fleet operations

Utah State UniversityAcademic Institution with Extensive Wireless Power Transfer Expertise. Wireless Power Transfer design & development

WAVETechnology Startup Producing & Deploying Wireless Chargers for Heavy Vehicles. Build and commercialize Wireless Power Transfer equipment

Seattle City LightLocal Government-Owned Public Utility. Providing grid power and consultation at Seattle charging site

Portland General ElectricLocal Public Utility. Providing power and consultation at Portland charging site

Romeo PowerBattery Technology Company. Battery development

Remaining Challenges and Barriers


Technical Challenges:

• Achieving the required energy transfer in the desired time without over-voltage or over-current in the battery system remains a concern. Early testing results indicate this can be achieved when the batteries are new; aging of the batteries may slow charge times.

• Thermal management of the batteries during charging is a concern. Simulation and analysis indicates the cooling system is properly designed, but testing may reveal unexpected issues.

• Electrical noise from the charger may affect CAN communications. Steps are being taken to reduce noise and to shield communication lines, but issues may arise once the full vehicle is in operation.

• Complete charging system efficiency including ground-side cooling and vehicle-side cooling may be low enough to reduce the attractiveness of this technology.

• This project will develop a proof-of-concept system of one BEV tractor and two wireless chargers for a total cost of $10M. Can this technology be produced at affordable costs when scaled to higher volumes?

Barriers:

• COVID has resulted in global component shortages and delivery delays. This has slowed progress in building the chassis and the charging system.

Proposed Future Research


Any proposed future work is subject to change based on funding levels.

2021 FY:

• Characterize the single stage AC-AC converter operation, transmitter coil and receiver coil, compensation tank and receiver diode bridge in terms of electric performance and thermal behavior.

• Complete the design and installation plans for each charger site (Seattle and Portland), and start the permitting process.

• Begin commercialization of the charging system.

• Complete the build of the vehicle and initiate functional testing (using 150 kW plug-in charger).

2022 FY:

• Complete the build of the charging equipment.

• Demonstrate the charging system off-vehicle at megawatt rate.

• Complete the installation of the grid power supply and charging equipment at each charging location.

• Install the charging receiver plate on the vehicle and validate power transfer to battery system.

• Commence commercial operations with the BEV tractor and wireless charging system.

Summary


Technical Accomplishments:

• Validated through physical testing that 462 kW-h of energy can be added to a 660-kW-h battery system in 30 minutes or less.

• Validated through physical testing that one inverter module (125 kW) can transmit power across a 300-mm [11.8 in] air gap at 93% DC-DC efficiency.

• Developed thermal management systems for the vehicle side to cool the charge plate, batteries, traction motor/inverter/transmission, auxiliary device motors and power electronics, in addition to cab HVAC. Conducted air flow and coolant flow simulations to show adequate cooling in expected worst-case scenarios.

• Completed vehicle layout and detail design drawings, and placed orders for all components.

• Developing vehicle control system to manage on-board components and systems – 50% complete.

elt_262Long-Range Battery Electric Vehicle with Megawatt Wireless Charging

(End of presentation)

long-range battery electric vehicle with megawatt wireless

Documents